What is Centerbore, Backspacing or Offset?

Wheel Diagram

A: Backspacing:
The distance from the mounting surface to the back of the wheel.

Bolt Pattern, Bolt Circle Diameter: 
The Bolt Pattern is the diameter of an imaginary circle that goes through the center of the bolt holes. Examples are 4×156 mm, 4×110 mm, 4×115 mm, 4×137 mm.

Centerbore: MOST UTV’s this does not apply
The size of the hole in the back of the wheel that centers the wheel properly on the hub of the car. Many aftermarket wheels will be drilled to a larger universal size, and uses hub rings to reduce the size to match the hub on the UTV for perfect centering. Generally speaking, a perfect hub size match and hub rings can be optional for vehicles that use lug nuts, 14+ XP1000 and 16+ XP Turbo’s have differant center bore than all RZR 14 and older.

The distance from the centerline of the wheel to the face of the mounting surface of the wheel that contacts the hub. A simple way to understand offset, is the lower the offset, the more the wheel will stick out, likewise, the higher the offset, the more the wheel will tuck. For example, a Polaris RZR generally uses around a +38 mm offset. So if you put a +15mm offset wheel on the UTV, the wheel is likely to stick out about 1 inch.